FIELD OF THE INVENTION
The field of beam scanning for the purpose of gathering information is rapidly advancing. The commercial application and importance of bar-code reading is well known and is now becoming more sophisticated with the introduction of high density two dimensional bar-code. Code 49, Code 1, and PDF 417 are examples of new bar-code standards that contain information in a two dimensional array.
As information densities increase, scanning with high speed scan patterns becomes necessary in order to read them rapidly. In addition to bar-code reading, the ability to read alphanumeric information is also of great commercial value. Other types of encoded information are being devised, and object recognition requiring scanning readout equipment is also of commercial importance.
As sophisticated portable requirements expand the demand for ever smaller high performance hardware increases.
The present invention provides a portable non-contact moving beam scanning device small enough to be comfortably held with the thumb and fingers like a pen, yet able to automatically scan a moving beam across a distant target containing information such as printed bar-code. The invention contains a novel in-line, or "axial," gyrating scan element, which can accept an input light beam at one end and cause it to emerge as a scanned beam at its opposite end, propagating about a neutral axis in the same general forward direction as it had upon entering the element. With this axial scan element, it is possible to construct an in-line arrangement of a light source and the scan device, thereby greatly simplifying and reducing space requirements for the optical layout of a scanner.
The scanning speeds may range from tens of scans per second to thousands of scans per second, at angles of forty degrees or more, and scanning in two dimensions is also possible. In its preferred embodiments, the invention is distinguished from prior art devices in that the beam passes through an oscillating scan element and generally maintains its original direction upon emergence from the element, rather than consuming the additional space needed to ultimately reverse beam direction.
Configured as a pen-sized and pen-shaped device, the invention also may contain an integrated light source (such as a diode laser), a beam focusing means, and a novel non-imaging light collector coupled to an information processing means for extracting information from the reflected light, as well as an inertially activated switch for turning the device on and off to provide a complete scanning system.
The entire system can be designed to fit into a miniature housing, which may be sized and shaped like a pen or wand, making possible the development of a new generation of compact laser scanning implements not previously available. In doing so the present invention overcomes many of the limitations of prior art devices such as contact-wands which must contact the bar code to be read and pistol grip bar code readers which are presently far larger than is desirable.
In particular, the invention relates to an integrated beam scanning module for use within the device, which can be easily fabricated in the form of a cylindrical module having dimensions of about three eighths of an inch in diameter by three quarters of an inch in length. The scan module's rugged housing may be made from a heat dissipating material (such as anodized aluminum) for conducting heat away from a laser diode.
The present invention also provides in a pen or wand size scanning system, the capability of generating two-dimensional scan patterns such as rasters or omni-directional patterns for reading printed indicia with little regard for orientation of printed material. It also enables one or two dimensional high density bar-code targets to be read at significant distances. This is done by means of high speed wide angle rastering scan patterns.
The present invention further includes methods for using a low mass pen-sized laser beam scanner mounted in ways that are impossible or cumbersome using current state of the art devices. For example, the device can be housed in a pen-sized tube allowing new mounting possibilities such as attachment to a light weight cap or safety helmet, to the temple of eyeglass frames, badges or a robot arm. Mounting several similar devices in a bundle can achieve overlapping scan patterns or redundancy in small spaces.
The invention also relates to methods for using the pen-size scanning system to inexpensively generate raster patterns. This is done by bending one's wrist while holding a device which produces a one-dimensional line scan, thereby deflecting the scanned beam to effect both X and Y-axis scanning, a process which may be termed "wrist rastering".
In addition, the invention also relates to methods for using the pen-size scanning system by visually impaired individuals to avoid obstacles and to read books printed in two dimensional bar-code or conventional print. It also relates to methods of using the scan system by individuals with various other physical disabilities, who are not adequately accommodated by the design and physical operating requirements of existing "pistol-grip" scanners.